1. Field of the Invention
by a knitted spacer fabric composed of at least two layers that are spaced apart from one another and pile threads extending therebetween, and wherein the textile surface can be at least regionally connected to a supporting frame.
2. The Prior Art
Textile surfaces for furniture such as, for example, chairs, backrests, sitting and reclining surfaces are disclosed in DE 201 18 250 U1 and AT 004 727 U1, respectively. In this case, the textile surface produced with a knitting machines is tentered between at least two frame parts. For reasons of simplicity, the entire textile surface is dimensionally knitted in the required shape. The textile surface furthermore features knitted borders with a narrower mesh width than the surfaces of the textile surface lying therebetween. The knitted borders have the shape of a knitted tube, wherein the tube edges can be pulled over rod-shaped frame elements of the furniture or inserted into holding grooves of the frame parts. The threads for the knitted textile consist of elastic plastic fibers such as, for example, Trevira CS 167F 64 X1.
A different type of upholstery for furniture is disclosed in EP 1 447 030 A1 and DE 203 02 364 U1, respectively. This upholstery features at least one knitted pile fiber fabric with an adjusting device arranged on at least one edge. This makes it possible to vary the prestress of the knitted pile fiber fabric and to thusly achieve a different firmness regardless of the state of stresses. The knitted pile fiber fabric is realized in a self-supporting fashion, wherein loops or a tube are/is directly knitted to the knitted pile fiber fabric in the edge region. The knitted pile fiber fabric has a superior air permeability such that no accumulation of heat or moisture occurs therein. These properties can be additionally promoted if the knitted pile fiber fabric is at least regionally made of a hydrophobic and/or hydrophilic material. In knitted pile fiber fabrics, the body movement also causes a movement of the air between the two cover layers such that additional mechanical ventilation of the upholstery can be entirely eliminated under certain circumstances. The knitted pile fiber fabric may furthermore consist of an antistatic material or a material that shields electromagnetic radiation. UV-resistant and fast-drying materials can furthermore be utilized.
In another knitted spacer fabric known from GB 2 009 266 A, the knitted spacer fabric is used as padding for furniture or seats. This knitted spacer fabric used in the form of padding may be additionally provided with a cover such that adequate ventilation can take place thereunder. The threads for the cover layers consist of nylon monofilaments and the pile threads consist of polypropylene. The threads may furthermore have different cross sections and also consist of film strips. The knitted spacer fabric can be realized such that it is easily washable and non-flammable.
A textile spacer material of variable thickness, as well as a method for the production thereof, is disclosed in EP 0 617 152 B1. This textile spacer material is produced on a knitting machine and features an upper and a lower cover layer of knitted material. The cover layers are connected to one another by means of at least one pile fiber structure, wherein the cover layers and the pile fiber structure consist of knitted material or partially knitted and partially woven material. The textile spacer material furthermore has a three-dimensional shape that is achieved by varying the pile fiber length, the pile fiber density and/or the pile fiber material, as well as by increasing and decreasing the stitches. The thickness of the spacer material is varied by changing the pile fiber length. Flat structures such as patterns, structural variations and/or color variations are realized on the cover layers. The material of a pile fiber is chosen such that it reacts in a reversible, partially reversible or irreversible fashion to chemical or physical influences. Suitable starting materials are all fiber materials that can be processed on knitting machines, e.g., monofilaments, multifilaments and multicomponent filaments. In addition, natural and synthetic fibers as well as wires or mineral material such as glass fibers or stone fibers can be used. The fiber material may also be covered by spinning, sheathed, spin-wrapped and/or surface-coated. If the pile fiber consists of a relatively rigid material, e.g., a monofilament, and the cover layers are made of a material that becomes shorter at elevated temperatures, it is possible to realize a contraction of the cover layers if they are heated while the pile fiber material essentially remains unchanged.
A known seat with a cushion of foamed plastic—according to WO 87/06894 of the same applicant—consists of a foamed plastic with a supporting member of an elastic open-cell plastic foam that has a first volume weight and a flame protevtive layer of an elastic open-cell foamed plastic that is provided with a flame retardant and has a second volume weight that differs from the first volume weight. The plastic foam and the flame protective layer are connected to one another, particularly by means of an expansion process, and surrounded by a hardly inflammable cover fabric. In order to achieve a sufficient air permeability of such a cushion, it was proposed to push needless through the cushion after its production in order to allow a corresponding air exchange. These cushions proved to perform well in practical applications, but it was determined that the seats were not sufficiently comfortable for the intended application in vehicles, primarily under extreme weather conditions or varying climatic conditions.
Known seats for public transportation means—according to DE 85 06 816 U—feature a seat cushion that is covered with a seat cover, wherein the seat cover and the seat cushion consist of a hardly inflammable and low-fuming material. In this case, a glass fiber mat is frequently arranged between the hardly inflammable seat cover and the seat cushion that usually consists of plastic foam so as to prevent the seat cover from burning through in the direction of the seat cushion. However, it was determined that flames affect such seats from the bottom in many instances and that the plastic foam has a tendency to develop significant smoke while it burns such that the public transportation means are quickly filled with so much smoke in case of a fire that the passengers become disoriented. Consequently, a flame-retarding plate is arranged underneath the seat cushion of this seat in the supporting frame thereof.
Seats with cushions of foamed plastic are widely used in the construction of modern vehicles. They are primarily used in rail and road vehicles, but also very popular in aircraft. Although rail vehicles are subject to very strict regulations with respect to the self-extinguishing properties and the smoke development of the materials used, the applicable regulations in the aircraft industry are even stricter. For example, seats authorized for use in aircraft need to undergo a test in which the cushions are directly exposed to the flame of a burner in the state in which they are subsequently installed. This flame directly acts upon the cushion for a duration of 2 minutes, whereafter the flame is extinguished or removed. The cushion is extinguished after 5 minutes if the flames are not already self-extinguished at that time. The weight loss of the cushion cannot exceed 10% after this fire test. In order to fulfill these extremely strict regulations and simultaneously provide the passengers with highly comfortable yet low-weight seats on long-distance flights, seat cushions of different soft, elastic open-cell plastic foams with different volume weights were treated with flame retardants and bonded together. One known vehicle seat of this type—according to EP 0 190 064 A1—consists of several layers of needle-punched nonwoven that are covered with a flame-retarding cover fabric. Reinforcing mats of metal or glass fibers are arranged between the cover fabric and the individual layers of needle-punched nonwoven in order to reduce damages due to vandalism. In light of the fact that the individual layers are bonded together and this vandalism protevtive layer features multiple intermediate layers, it is hardly possible to achieve sufficient ventilation of this known vehicle seat.
In another known seat for aircraft, the complicated three-dimensional shape of the seat cushions is simplified by realizing the one-piece supporting member in the form of a part that is integrally expanded in a mould and treated with flame ratardants, wherein the surface of this expanded part is covered with a flame protective layer and then with a flame-retarding cover fabric. However, these known seats cannot fulfill the safety regulations and test requirements for aircraft seats that recently became even stricter and are also insufficient with respect to cost-efficient cleaning and maintenance times.
Other seat cushions, particularly for aircraft, are disclosed in DE 42 09 468 A1 and DE 44 38 018 A1, wherein the supporting member of the seat cushion consists of at least two different components that are connected to one another, particularly in a separable fashion. In this case, one component forms a supporting element and another component forms an upper element. The supporting element may consist of several parts, wherein an additional insert is arranged between a front and/or rear edge of the supporting element and/or upper element and approximately in a central region thereof, namely at least over part of the thickness of the supporting element and/or upper element. This insert is harder than the supporting element and/or the upper element, but the volume weight of the insert is lower than the volume weight of the supporting element. It is furthermore possible to arrange an additional supporting device, particularly a spring core, in the support section of the supporting element.